Cisco Systems 1600 manual Switching Paths, Receiving the packet

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Cisco IOS software creates these rings on behalf of the media controllers and then manages them jointly with the controllers. Each interface has a pair of rings: a receive (RX) ring for receiving packets and a transmit (TX) ring for transmitting packets.

Receive rings have a constant number of packet buffers allocated to them that equals the size of the ring. The show controllers command below displays the size and the location of the receive and transmit rings:

router#show controllers ethernet 0

QUICC Ethernet unit 0 using SCC1, Microcode ver 3 Current station address 0060.5cbc.3d41, default address 0060.5cbc.3d41

idb at 0x2AFE0EC, driver data structure at 0x2AEF820 SCC Registers:

General [GSMR]=0x0:0x1088003C, Protocol−specific [PSMR]=0x80A Events [SCCE]=0x0000, Mask [SCCM]=0x001F, Status [SCCS]=0x0002 Transmit on Demand [TODR]=0x0, Data Sync [DSR]=0xD555 Interrupt Registers:

Config [CICR]=0x00368461, Pending [CIPR]=0x0100C402

...

RX ring with 16 entries at 0xFF00420, Buffer size 1524

Rxhead = 0xFF00458 (7), Rxp = 0x2AEF858 (7)

00 pak=0x2B00F34 buf=0x2D8A48C status=9000 pak_size=0

01 pak=0x2B02B24 buf=0x2D8F55C status=9000 pak_size=0

02 pak=0x2B01D2C buf=0x2D8CCF4 status=9000 pak_size=0

03 pak=0x2B00CE0 buf=0x2D89DD0 status=9000 pak_size=0

...

TX ring with 4 entries at 0xFF004A0, tx_count = 0

tx_head = 0xFF004A0 (0), head_txp = 0x2AEF898 (0) tx_tail = 0xFF004A0 (0), tail_txp = 0x2AEF898 (0)

00 pak=0x0000000 buf=0x0000000 status=0000 pak_size=0

01 pak=0x0000000 buf=0x0000000 status=0000 pak_size=0

02 pak=0x0000000 buf=0x0000000 status=0000 pak_size=0

03 pak=0x0000000 buf=0x0000000 status=2000 pak_size=0

...

The highlighted entries are explained as follows:

RX ring with 16 entries at 0xFF00420, Buffer size 1524 : The size of the receive ring is 16 and it begins at the address 0x0xFF00420 in I/O memory. The size of the buffers for the Ethernet interface is 1524.

TX ring with 4 entries at 0xFF004A0, TX_count = 0: The size of the transmit ring is 4, it begins at the address 0xFF004A0 in I/O memory and there are no packets awaiting transmission on this interface.

Switching Paths

The description below is based on the book Inside Cisco IOS Software Architecture, Cisco Press1.

1 − Receiving the packet

Cisco 1600 Series Router Architecture

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Contents Cisco 1600 Series Router Architecture Table of Contents Hardware Overview IntroductionIntroduction Hardware Overview Block Diagram Memory Details Router−1600#show memory summaryCisco 1600 Series Router Architecture Boot Sequence Boot system flash slot0c1600−sy−l.122−1a.bin Private Buffer Pools Receive Rings and Transmit RingsSwitching Paths − Receiving the packet− Switching the Packet Related Information − Transmitting the PacketUpdated Oct 10 Document ID
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1600 specifications

Cisco Systems 1600 series routers are well-regarded in the networking industry for their reliability, versatility, and performance. Designed to meet the needs of small to medium-sized businesses, the Cisco 1600 series is primarily oriented towards providing robust connectivity for branch offices and remote sites.

One of the most significant features of the Cisco 1600 series is its modular architecture. This allows users to customize their routers with various interface cards, enabling support for different types of WAN technologies, including serial, ISDN, and Frame Relay. The modular design not only enhances flexibility but also extends the lifespan of the equipment, as businesses can upgrade their capacity and functionalities according to evolving demands.

Another key characteristic of the Cisco 1600 routers is their advanced routing capabilities. These devices support a wide range of routing protocols, including RIP, OSPF, EIGRP, and BGP. This versatility ensures seamless integration into existing network infrastructures, facilitating the scalability and adaptability that modern networks require.

Security is also a crucial aspect of the Cisco 1600 series. Incorporating features such as access control lists (ACLs) and support for Virtual Private Networks (VPNs), these routers help businesses safeguard their sensitive data during transmission. Enhanced security features allow companies to implement secure remote access for employees, thereby maintaining productivity without compromising safety.

In addition to routing and security, the Cisco 1600 series boasts Quality of Service (QoS) capabilities. This technology enables better management of network traffic, ensuring that critical applications receive the bandwidth they need for optimal performance. By prioritizing important data flows, businesses can enhance user experience and minimize disruptions across their network.

The Cisco 1600 series routers are also equipped with user-friendly interfaces and management tools. Cisco's IOS software platform provides a command-line interface (CLI) and web-based graphical interface for straightforward configuration and monitoring. This simplifies network management tasks and reduces the learning curve for IT personnel.

In summary, the Cisco Systems 1600 series routers offer a significant combination of modularity, robust routing protocols, enhanced security measures, Quality of Service features, and user-friendly management options. These characteristics make them an excellent choice for small to medium-sized enterprises looking to establish a reliable and secure networking infrastructure. With the continued evolution of networking technologies, the Cisco 1600 series stands as a dependable solution for businesses navigating an increasingly complex digital landscape.